You cannot combine your vip with another coupon on the same item but you can use it on all the other items at the same time with the coupon...did i make sense????
for example if you bought 3 items 2 on sale already and one regular price...you can use 1 coupon for the regular price item and still use your vip card on the other 2 items at the same time, so the 10% applies only to the sale items.